Consider the following hypothesis test ;

$H_0 : \mu ≥20$

$H_1 : \mu < 20 $

A sample of 64 provided a sample mean of 19.5. The population standard deviation is 2. The value of the test statistic is :

-2

The correct answer is Option (2) → -2

Sample size, $n=64$

Sample mean, $\bar x=19.5$

Population standard deviation, $σ=2$

Under $H_0$, we use $μ_0=20$

The test statistics,

$z=\frac{\bar x-μ_0}{σ/\sqrt{n}}=-\frac{0.5}{0.25}=-2$